


Beach Day

by bluecrownedmotmot



Category: Undertale (Video Game)
Genre: Established Relationship, F/F, Fluff, Intimate relationship
Language: English
Status: Completed
Published: 2016-07-12
Updated: 2016-07-12
Packaged: 2018-07-23 01:20:03
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,538
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7461003
Author URL: https://archiveofourown.org/users/bluecrownedmotmot/pseuds/bluecrownedmotmot
Summary: <blockquote class="userstuff">
              <p>Post pacifist ending. Alphys and Undyne have a super hot time at the beach.</p>
            </blockquote>





	Beach Day

The city-side shore was sweltering. Undyne carried the bulk of the beach paraphernalia, including a huge umbrella, but it was Alphys who couldn't seem to manage her one item, the cooler, without constantly tripping.

“Girl, do you want me to get that instead?” asked Undyne.

“N-no. It's just the s-sand keeps getting in my way,” said Alphys.

“Well, I can't help with that. This is the beach. Come on, Alphys. How about you just take the umbrella? It's way lighter.”

“N-no... It's too big for me, it'd be even worse-” Alphys tripped yet again. Luckily, she was short, and thus close to the ground to begin with.

“Hey, look at that spot over there. That's perfect,” exclaimed Undyne, really wanting to walk farther out to get away from the crowds, but wanting even more to end her girlfriend's misery as soon as conceivably possible.

They staked out their own space. Undyne set up the umbrella and Alphys unrolled the blanket.

“We can walk along the beach later maybe, just leave all this stuff here. There are so many people. I'm sure we can ask someone to keep an eye on these things,” reasoned Undyne, partially to herself. She let her gorgeous crimson hair free from her ponytail and shook her head.

Alphys plopped down on the blanket. She was unsure if she really liked the beach. She was so incredibly hot she caught herself leaving her mouth open to try to regulate her temperature.

 

“Let's go swimming!” shouted Undyne, running across the hot sand to the water, hair billowing out behind her.

“S-swimming... Yeah...” whispered Alphys nervously, trailing along.

“Come on, Alphys! I can tell you're sweating like crazy! Get in!”

“W-what if there's a d-dangerous undertow... Or I start drowning, and I pull you down, and our lungs fill with water, and we both die horrible deaths...”

“Alphys.”

“Undyne. I, uh... Can't swim.”

“Alphys!” Undyne laughed. “Why would you neglect to mention this when I proposed going to the beach? Why can't you swim?”

“We didn't even _have_ enough water in Hotland to swim. I probably sink like a rock anyway...”

“Baby, look at how shallow it is. You don't need to swim. But I'll teach you, you silly thing. I'm an expert!”

Alphys gingerly waded in. There was no tow and barely any waves.

“Isn't it refreshing in here?” asked Undyne.

“Yes,” peeped Alphys.

“Okay! Now just come out here... You're gonna learn to tread water. Look, I can stand here, but you'll be over your head. There's no way in hell you could drown me. Give it a shot. Please?”

“Okay!” replied Alphys, doing her best to fake bravery.

“What a good sport you are,” encouraged Undyne, as Alphys stepped closer and closer. “I promise I'll buy you a Nice Cream later.”

“Thanks. I'm ready to d-die now.”

“ _Alphys._ ”

 

Alphys had managed treading for five minutes when they were done. Undyne was proud of her. They dried off back under the umbrella, walked a short distance to the retaining wall, and climbed up. There was a familiar rabbit-like monster standing by his cart. He seemed absorbed by something on his phone.

“I can't believe he found me. I can't believe he keeps messaging back,” he sighed dreamily to himself.

“Excuse us?” said Alphys.

“Huh? Oh, I'm so sorry,” he apologized, blushing. He dropped his phone into the cart, between cartons of Nice Cream. “ _Shoot_.” He giggled and fished the phone out with his lanky arm, before giving the two fellow monsters a radiant grin. “So, would you ladies like Nice Creams?”

 

They ate their Nice Creams, green tea for Alphys and tangerine for Undyne, sitting on the retaining wall. They looked out at the ocean.

“So, how are you liking it up here?” Undyne asked.

“It's incredible. It's better than I imagined. I have a hard time getting over the fresh air, the sunlight. And humans are way more complicated than I ever imagined.”

“Yeah, I know! Humans may not run around with giant swords...”

Alphys hid her face with one hand.

“But all the stuff up here is the coolest,” Undyne laughed. “And actually, I just did take a kendo class at the Y. It was like all my anime dreams had come true.”

Alphys peeked out through her fingers. “Did you really?”

“Yep. Do you want to come with me next time?”

“Maybe I'll watch. I need a h-hobby that's not work or something I can do by myself. I'd like to get out for fun more. My job is stressful sometimes.”

Undyne nodded. Alphys had been building prosthetic creations for humans. Apparently some of the technology she had developed while constructing an android body for a monster was more advanced and useful to highly physical beings than she had realized. Humans, however, struggled for longer with adaptation and had a wider variety of challenges. Many issues had no solutions she could yet discover. She saw to it that her interactions with actual humans were minimal (she still felt guilty about direct contact with living creatures due to the amalgamate incident) but it was rewarding when someone was able to adjust to something she designed and insisted upon meeting her in person.

“Come to class with me next time,” said Undyne. “I'm sure you'd like it, nerd.”

“O-okay. I'll just put in on my calendar so I don't forget.” Alphys fiddled with her phone.

Undyne kissed her girlfriend on the cheek. Alphys blushed.

“Why are you so shy?” Undyne asked, with a chuckle. “Aren't we dating?”

Alphys looked at Undyne out of the corner of her eye. Her girlfriend's lithe, well-defined body and blue skin looked amazing in contrast against her yellow bikini.

“How did that happen?” Alphys mumbled.

“It happened,” explained Undyne patiently, “because I like you and you like me. Simple as that. Hey girlfriend, I was hoping... Maybe we could take a walk down the beach? I hear it starts to be all dunes and sea grass past that groyne way out there. And no people. Could we check that out?”

“That's pretty far,” observed Alphys.

“Oh, we could rest when we got to a nice spot.”

“What about our stuff?”

Undyne nodded to Lesser Dog. “A former Royal Guard. Looks like they're going to be here a while perfecting sand-dogs. They'll watch our stuff, make sure it doesn't go out to sea when the tide comes in.”

“They look kind of busy.”

“But they'll do a favor for their old captain!” Undyne put her fingers in her mouth and whistled. Lesser Dog perked up and came bounding over. “See?” she laughed.

 

The walk was long, but Alphys and Undyne took their time and chatted the entire way. They brought with them just one bag and the blanket. When they reached the rock groyne, they climbed over together. On the other side, there was barely a trace of human civilization. The only indication was wooden fencing here and there to prevent damage to the fragile dunes. Sea grass swayed peacefully beyond the fences. Beach plums were visible on scattered bushes. Birds swooped down into the mounds and then out to sea again. The surf was rougher here, and the crash of the waves could be heard with regularity.

“People must not come out here a lot,” remarked Alphys. “It's pristine.”

“Yeah. Really tranquil.” Undyne yawned. “Let's sit and watch the waves.”

They unfurled the blanket and lay down prone. Undyne dozed off after several minutes. Alphys closed her eyes and let her girlfriend sleep.

 

Undyne blinked awake after fifteen minutes or so. “Man, I had the weirdest dream.”

“Of what?” wondered Alphys.

“I was... A mermaid? And someone in a diving suit was chasing me. I tried to lose them by going through a reef, but no matter which way I swam, the diver caught up. Then there was a big rock cove and I was trapped! So I turned around and threw a spear! I missed the diver, but then they took off their helm... And it was you! But you had gills and frills and could breathe underwater. You were so totally flustered. You explained that you just wanted to study me. I thought you were pretty cute, so maybe that wouldn't be so bad... But then I woke up.”

“Ha ha, that's pretty weird. I wonder where that came from? You know, I had this theory about alternate universes-”

“Pffh. I think it came from being by the ocean... And thinking about how adorable you are.” She smiled slowly at Alphys. “You know, there's no one around for miles...”

“I was h-hoping you'd suggest something like that,” giggled Alphys.

 

Undyne pushed Alphys down onto the blanket. Her face was close up against her girlfriend's. Undyne snaked her tongue into Alphys' mouth. Alphys touched the sides of Undyne's face and kissed back. Soon Alphys was kissing harder than her girlfriend was. Undyne tried to pull back to breathe, but Alphys wouldn't let her. Undyne waited until Alphys was satisfied and then sat back up.

“Wow, that was passionate! Alphys. What kisses. I'm impressed.”

“Maybe I got a little carried away.”

Undyne laughed and then narrowed her eyes, taking on an intense tone. “It was hot.”

Alphys pulled her girlfriend back down and flicked her tongue against Undyne's ear. Undyne shuddered. Alphys grazed Undyne's chest, just barely, to give her girlfriend the chills.

“I love when you touch me,” Undyne breathed.

“Well, I love touching you,” replied Alphys.

She ran her claws down Undyne's defined abdomen, parted her hands to fall down her girlfriend's sides, and traced her obliques.

Undyne settled down onto her girlfriend and snuggled her face into Alphys' boobs.

 

Undyne propped herself back up after a moment, so she could rub in slow circles with her fingertips on Alphys' bathing suit below her navel and gradually travel down. Alphys wiggled nervously. Undyne gave her a toothy grin. She felt for Alphys' clit and stroked through the fabric. Alphys squirmed and moaned. Undyne watched her face and continued for a while before pulling down Alphys' bathing suit. Alphys squirmed the suit off and kicked it away.

Undyne surveyed Alphys' body and smiled. She touched Alphys' vulva and rubbed. Alphys panted and pawed against Undyne her with her feet. Undyne used two fingers to spread her labia apart and bent her head to Alphys. Undyne licked Alphys' clit and lapped at her gently. The tongue was warm and wonderful. Alphys felt euphoric shakiness every time there was a change of direction and her girlfriend's nimble tongue found just the right spot.

Undyne came back up to kiss Alphys, and Alphys took the opportunity to pull off both pieces of Undyne's suit. Undyne was so sleek and powerful, and her lower body was flat and neat between her legs. Alphys caressed the tight creases of muscle above her girlfriend's hips, and followed them down. She lightly glanced over Undyne's clit and continued along the closed ridge of Undyne's slit. Her fingers came away wet.

Undyne shivered. “It's insane how turned on I am right now,” she moaned.

“Me too,” panted Alphys. “Why is it so great?”

“For me,” said Undyne, “it's because I like you so much. It's just so intense and wonderful.”

“Yeah, that's it for me too!” gushed Alphys.

Alphys kissed her girlfriend again. She slid a couple of her fingers into Undyne and curled them forward gradually. Undyne gasped. Alphys rubbed with the fingers, feeling the texture of the internal tissue, and used her thumb to on Undyne's clit.

“Oh for fuck's sake,” whispered Undyne, tossing around. She moaned and twitched. Alphys continued, applying pressure with her fingers, taking it away, changing the pattern of how she stroked Undyne's clit with her thumb. Undyne was shaking and whimpering, and had collapsed down entirely on top of Alphys, when Alphys finally pulled her hand back.

 

“I had no idea it was possible to come that many times,” Undyne said, when she had relaxed at little.

“Really?” laughed Alphys guiltily. “Because uhhh... Sometimes I spend all afternoon in the shower with the hand-held showerhead...”

“Alphys!” Undyne howled.

“Ummm, Hotland was _hot_ , okay? I was always so sweaty I had to wash off... It's not my fault that I discovered... Fun activities while I was there.”

“Okay, you filthy thing. You deserve a taste of your own medicine.” Undyne slid her hand to Alphys' clit. She sucked on Alphys' breast, which Alphys enjoyed quite a lot. Undyne insinuated her hand between her girlfriend's thick thighs and gently plunged her fingers into Alphys. She applied pressure, and stroked Alphys' clit until Alphys was unable to help herself from saying Undyne's name over and over.

“Alright, alright... I am so lightheaded I'm seeing stars...” Alphys said eventually, in a quavering voice. Undyne took back her hand and lifted her head from Alphys' breast, leaning down again to give the opposite nipple a parting delicate tweak with her teeth. Alphys peeped with surprise, feeling the pinch like an electric current down her spine, rippling downward into a final orgasm.

“Good!” laughed Undyne. “That's how I felt. I had to seek revenge.”

“I hope you're satisfied,” Alphys giggled. “I sure am.”

“No question,” Undyne got off of Alphys and held her close from behind. “You're the greatest girlfriend ever. You satisfy me in every possible way.” She snuggled her head against Alphys' neck and kissed her shoulder. “Love ya, Alphys.”

Alphys took her hand and squeezed it in hers. “I love you, too.”

 

They ran into the water totally naked and swam again. The waves were stronger, and Undyne kept Alphys safely away from the slight current toward the submerged part of the groyne, but the water was incredibly refreshing. They laid back down on the blanket and let the salt water evaporate off their bodies.

The two dozed off briefly in the sun. Undyne woke to notice that Alphys was napping curled in a ball, her tail against her forehead. When Undyne shifted position onto her back, Alphys opened her eyes too.

“Do you always sleep like that, cutie?” teased Undyne.

“Uhhh... Only s-sometimes?” Alphys stretched out and used Undyne's stomach as a pillow.

They both feel back asleep, this time for much longer.

 

Something cold was tickling their feet... Undyne woke up fast. Waves had just reached them. The tide had come in, all right.

_Oh no..._

“Alphys! Get up! Our stuff!”

 

They pulled on their swimsuits frantically and raced back along the beach as fast as they could manage. Finally, they reached the edge of the city beach again.

Nearly everyone had gone home for the day. Lesser Dog barked happily at them. Thousands of sand-dogs littered what remained of the beach. There had probably been even more that had been leveled by the tide. Somehow, Lesser Dog had taken their umbrella down, folded their towel, and neatly stacked everything safely by the retaining wall.

“You're wonderful!” gushed Undyne, rushing up to the dog. “How can we ever repay you?”

“Woof!” said Lesser Dog. The dog bumped Undyne's hand.

Alphys, despite being winded, got it immediately.

“I think, I think, I think... Oh my god... Sorry, gotta breathe... I think we could do that,” she panted, patting the dog obligingly.

**Author's Note:**

> http://motmotfluttersforth.tumblr.com/


End file.
